Process for biological deinking of office waste paper

ABSTRACT

This invention relates to a biological process for deinking of office waste paper and more particularly, the present invention relates to a biological process for deinking of xerographic and inkjet printed paper using a gram-negative coccoid bacterium deposited at National Institute of Oceanography, Dona Paula, Goa 403 043, India having accession No. NIO/DI/32 and being deposited at an international depository ______ having accession number ______ and also deposited at Microbial Technology, Chandigarh, India having accession No. ______.

FIELD OF THE INVENTION

[0001] The present invention relates to decolorization of office wastepaper using microorganisms from marine habitats. More particularly, thepresent invention relates to a process for biological deinking ofphotocopied and inkjet-printed paper or toner photocopied paper pulpusing a gram-negative coccoid bacterium deposited at National Instituteof Oceanography, Dona Paula, Goa 403 043, India having accession No.NIO/DI/32 and being deposited at an international depository ______having accession number ______ and also deposited at MicrobialTechnology, Chandigarh, India having accession No. ______.

BACKGROUND OF THE INVENTION

[0002] Paper manufacturing is a major industry and a continuouslygrowing one. Increased production of paper imposes a severe demand onplant raw material and thus harms the environment. Recycling of usedpaper is an alternative that can alleviate the stress that is exercisedon the environment. The three major sources of raw material for suchrecycling are newsprint, photocopied paper and inkjet—printed papers.Recycling of paper requires the removal of the printing ink from theused paper, called deinking, so that the processed material is brighter.Printing on paper is accomplished by using two types of inks, the impactand the non-impact inks. In impact inks, used for newsprints, the inkdoes not fuse with the paper and is, therefore, easy to remove ordisperse during the deinking, or recycling process. Such recycling isnow well known and has been carried out for years. On the contrary,non-impact inks used in photocopying, ink-jet printing and laserprinting results in the ink fusing with the paper and makes itnon-dispersible, thus rendering the deinking process much more difficult(Jeffries, 2002). The toners used for photocopying generally containiron oxide (about 55%), olefins (about 5%) and plastic or polymer(Website:http://www.eng-tips.com).

[0003] Various hydrolytic enzymes such as cellulase, lipase, amylase ofbacterial or fungal origin, individually or in combination have beenused for deinking of office waste paper.

[0004] (i) A reference may be made to a publication wherein, a methodfor deinking of xerographic and printed paper, collectively calledoffice waste, includes applying deinking solution to the paper to bedeinked, the deinking solution being composed of a cleaning solution anda surfactant, abrading the paper to remove the ink from paper, andwashing the paper to remove the deinking solution from the paper (U.S.Pat. No. 6,022,423 Bhatia, S. 1996 Method for deinking paper dtd2000-02-08). However, this patent involves using a special device fordeinking of whole sheets and cannot be used on pulp.

[0005] (ii) Another reference may be made to wherein, a monocomponentcellulase is used for removal of ink and toners from printed paper (U.S.Pat. No. 5,525,193 Neal, E., Steven, B. E., Hans, H. C. 1994. Use ofmonocomponent cellulase for removing inks, coatings and toners fromprinted paper). The technique of isolating monocomponent cellulase frommicroorganisms by various purifications, chromatographic steps is timeconsuming and expensive.

[0006] (iii) A reference may be made to a publication wherein,endogluconases and hemicellulases from several fungi are usedeffectively for deinking of xerox and laser-printed paper (Gubitz, G.M., Mansfield, S. D., Bohm, D. Saddler, J. N. 1998. Effect ofendoglucanases and hemicellulases in magnetic and flotation deinking ofxerographic and laser-printed papers. Journal of Biotechnology.65:209-215). As mentioned above the enzyme technology is still anexpensive one for using on a large scale.

[0007] (iv) A reference may be made to a publication, wherein deinkingof laser printed or xerographic paper is done using enzyme containing aresistant binder. Enzyme is added in the specified form to improve speckremoval (Landley, J. G. Stockwell, J. O. 1997. Enzyme deinking of paper.Patent Number. GB 2304741 dated 26.03.97). As with the above references,the technology to produce enzymes, their purification and application isan expensive process.

[0008] (v) A reference may be made to a publication, wherein deinking ofoffice waste paper is carried out by contacting the pulp with a deinkingagent containing enzymes cellulase, preferably active at pH 4 to 8. Thetreated paper is used in the production of newsprint and high qualitypaper (Jobbins, J. M. Asbrand, Jr. G. R. 1996. Composition and processfor deinking office waste paper. Patent number: EP 717144 dated19.06.96). As with the above references, the technology to produceenzymes, their purification and application is an expensive process.

[0009] (vi) A reference may be made to a publication, wherein deinkingof waste paper is achieved by incubating the paper pulp with cellulaseat 40° C. for 1 hour under pressure. Following dissociation of inkparticles, the resulting washed pulp is brighter (Mitsubishi HeavyIndustries. 1994. Deinking of waste paper. Patent number: JP06346390dated 20.12.94). As with the above references, the technology to produceenzymes, their purification and application is an expensive process.

[0010] (vii) A reference may be made to a publication, wherein deinkingis achieved by using lipase to remove ink from used paper. The procedureis carried out under neutral or alkaline conditions which producesregenerated pulp having enhanced brightness (Novo. 1990. Removing inkfrom used paper. Patent number: JP2160984 dated 20.06.90).

[0011] (viii) A reference may be made to a publication, wherein deinkingof waste paper is done by using the yeast Hansenula polymorpha, whichdegrades the ink-based resin (Jeonju-Paper. 1993. Waste-paper deinking.Patent number: KR 9303705 dated 08.05.93). However, the ink floats onthe surface and the pulp has to be extensively washed to remove thedetached ink.

[0012] (ix) A reference may be made to a publication, whereindecolorization of Indian ink is achieved by using thermostable alkalinecellulase from a Bacillus sp (Kao. 1998. A microbiologically producedthermostable alkaline cellulase and a process for its preparation.Patent number: JP 10313859)

OBJECTS OF THE PRESENT INVENTION

[0013] The main object of the present invention is to provide a processfor decolorization of waste paper.

[0014] Another object of the present invention is to provide a processfor biological deinking of photocopied and inkjet-printed paper pulpusing a gram-negative coccoid bacterium deposited at National Instituteof Oceanography, Dona Paula, Goa 403 043, India having accession No.NIO/DI/32 and being deposited at an international depository ______having accession number ______ and also deposited at MicrobialTechnology, Chandigarh, India having accession No. ______.

SUMMARY OF THE INVENTION

[0015] The present invention provides a process for decolorization ofpaper pulp and more particularly, the present invention relates to aprocess for biological deinking of photocopied and inkjet-printed paperpulp using a gram negative coccoid bacteria deposited at NationalInstitute of Oceanography, Dona Paula, Goa 403 043, India havingaccession No. NIO/DI/32 and being deposited at an internationaldepository ______ having accession number ______ and also deposited atMicrobial Technology, Chandigarh, India having accession No. ______.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0016] Accordingly, the present invention provides a process forbiological deinking of office waste paper inclusive of xerographic andinkjet-printed paper printed with non-impact and non-dispersible ink,said process comprises:

[0017] (a) growing coccoid bacterial isolate deposited at NationalInstitute of Oceanography, Dona Paula, Goa 403 043, India havingaccession No. NIO/DI/32 and being deposited at an internationaldepository ______having accession number ______ and also deposited atMicrobial Technology, Chandigarh, India having accession No. ______, ina nutrient broth containing beef extract, peptic digest of animal tissueand salinity ranging between 30 to 35 parts per thousand for at least 4days;

[0018] (b) adding the resulting biomass of step (a) at 20% concentrationto inoculate paper pulp diluted to at least 6% consistency suspended insea water with salinity diluted to 50%;

[0019] (c) incubating the inoculated pulp for a minimum period of 96hours followed by diluting the pulp tenfold;

[0020] (d) adding 1% by wt. of a surfactant and aerating for at least 10minutes with compressed air to let the stray residual ink particles andcontaminants flow out of the container, and

[0021] (e) filtering the pulp of step (d) over a funnel under suction,to get a sheet of pulp with uniform thickness and reading the brightnessby radiance measurement.

[0022] In an embodiment of the present invention, wherein in step (a),the bacterium is grown for a minimum of 4 days in nutrient brothcontaining beef extract and peptic digest of animal tissue in sea waterwith salinity diluted to 50%.

[0023] In another embodiment of the present invention, wherein in step(b), the resulting bacterial biomass is concentrated by centrifugationand diluted to get final optical density of 1.0 measured at 660 nm in aspectrophotometer.

[0024] In yet another embodiment of the present invention, the dilutedbacterial culture is inoculated to at least 6% pulp suspended inseawater with salinity diluted to 50% and incubated for a minimum periodof 4 days within to completely beach the pulp.

[0025] In still another embodiment of the present invention, theresulting bleached pulp is diluted tenfold, to which 1% surfactant isadded, aerated using compressed air, and any free residual ink particlesand contaminants are allowed to flow out of the solution.

[0026] In a further embodiment of the present invention, wherein afterstep (d) the xerographic or inkjet-printed paper is soaked in hot waterfor 1-2 hours and macerated after adding 1% surfactant to pulp.

[0027] In one more embodiment of the present invention, the paper ismacerated using conventional mixers.

[0028] In one another embodiment of the present invention, wherein instep (e), the washed pulp is filtered over a Buchner funnel undersuction to get a pulp sheet of uniform thickness.

[0029] In an embodiment of the present invention, the pulp sheet ispressed at 60° C. for a minimum of 4-5 hours to make it uniform anddried.

[0030] In another embodiment of the present invention, the radiance ofthe resultant sheet is read from 412 to 684 nm and the radianceexpressed as Lux units (LU) {wherein one LU is equivalent toμW/cm²/nm/Sr}.

[0031] In still another embodiment of the present invention, the pulpsheet made out of recycled paper is used as a reference.

[0032] In yet another embodiment of the present invention, wherein insteps (a) and (b), pure water containing 1.5% by wt of sodium chloridecan be used in the place of sea water.

[0033] Deinking of paper is a limiting factor in recycling of paper.Newsprint and office waste paper is generally deinked using chemicalswhich go into the effluent and cause pollution of the water bodies. Thenewsprint or offset printing is done using dispersible or non-impact inkwhereas laser, xerographic and ink-jet printer ink does not disperse andis also called impact ink. There are several patents describing variousmethods of deinking by using hydrolytic enzymes such as cellulase,hemicellulase and lipase of microbial origin which release tonerparticles from fibers. However, enzyme action is affected by the paperconstituents in the deinking condition. The chemically pulped fibers aremore susceptible than mechanically pulped fibers. Office waste paper ishigh in laser and toner content and the technology for taking the tonerparticles out is not very good at the moment (Jefferies, 2002).

[0034] In the present invention, the Applicants report a process fordeinking of office waste paper comprising xerographic and ink-jetprinted paper by a bacterium isolated from marine sediment of an estuaryin Goa, India. The salinity of the water at the time of isolation wasaround 15 parts per thousand which is equivalent to half-strength seawater.

[0035] The present invention provides a process for biological deinkingof office waste paper comprising xerographed, ink-jet printed, andsimilar other non-impact ink printed papers. The process is achieved byusing a coccoid bacterium deposited National Institute of Oceanography,Dona Paula, Goa 403 043, India having accession No. NIO/DI/32 and beingdeposited at an international depository ______ having accession number______ and also deposited at Microbial Technology, Chandigarh, Indiahaving accession No. ______, said culture may be grown in nutrient brothcontaining beef extract, and peptic digest of animal tissue and preparedwith sea water with its salinity diluted to 50%.

[0036] The present invention more particularly provides a processwherein the aforesaid pre-grown bacterial culture is inoculated onto theoffice pulp suspended in seawater with its salinity diluted to 50% andincubated for a minimum period of 4 days to decolorize the paper pulp.

[0037] The paper pulp becomes brighter, the black ink is totallydecolorized and the supernatant water remains clear. The water needs tobe simply drained to recover the deinked pulp. The pulp can be dilutedtenfold Optionally to remove any free residual ink particles and othercontaminants. Conventional surfactant at 1% concentration may be addedto the diluted paper pulp, aerated for at least 10 minutes by which theparticles float and go out of the pulp slurry. The washed pulp can befiltered over a large funnel under suction and dried at 60° C. for atleast 6 hours to obtain decolorized paper pulp.

[0038] The organism given in the present invention is a gram-negative,coccoid bacterium isolated from coastal marine sediment. The coccoidbacterium has been deposited at National Institute of Oceanography, DonaPaula, Goa 403 043, India having accession No. NIO/DI/32 and beingdeposited at an international depository ______ having accession number______ and also deposited at Microbial Technology, Chandigarh, Indiahaving accession No. ______. Said bacterium can be grown in nutrientbroth containing beef extract, peptic digest of animal tissue, preparedwith sea water with salinity diluted to 50% and having a pH of at least7.5. The bacterium when grown in nutrient agar medium appears ascircular colonies off-white in colour, having 2 mm diameter colonies inthe beginning and growing to a size of 5 mm within 3-4 days. Thebacterium is capable of producing lipase and amylase in the presence ofTween 80 and starch respectively. It is fermentative andcatalase-negative bacterium. The bacterium is grown at room temperature(30° C.) for about 4 days, the bacterial cells are collected bycentrifugation under sterile conditions, diluted appropriately to getoptical density of 1 at 660 nm. Xerographic, ink-jet printed paper andother papers having printed with impact ink are pulped by soaking in hotwater for a minimum of 2 hrs, macerated in a domestic mixer withsurfactant such as Tween 80. An example for the process for deinkinginvolves suspending such a pulp at least at 6% consistency in seawaterwith salinity diluted to 50%, inoculating with 20% bacterial suspensionprepared as described above and incubating at room temperature for aminimum of 4 days to get completely decolorized pulp and the ink isdisappeared from water also. The pulp can be diluted, aerated frombottom to remove free contaminating particles, salts and bacterialcells. A surfactant such as Tween 80 can be added at 1% concentrationfor flotation of any residual ink particles. The pulp is filtered over aBuchner funnel under suction, pressed with flat stainless steel platesto make the pulp sheet uniform in thickness. The radiance of theresultant sheet is read from 412 to 684 nm and the radiance expressed inLux units (Lu). One LU is equivalent to μW/cm²/nm/Sr. The ratio ofradiance between recycled paper purchased from the market andbiologically deinked paper is taken as a measure of brightness.

[0039] In a typical example plain toner powder of xerox machinesuspended in seawater with its salinity diluted to 50% also becamecompletely colorless within 7 days after inoculating it with the saidbacterial suspension.

[0040] Most of the organisms used for biological deinking release inkparticles from the fibers and they need to be subsequently washed offfrom the pulp. In the process described in the present invention, thisproblem does not arise as the ink and toner particles are totallydecolorized. The method is very cost effective as the only step involvedis raising the bacterial inoculum in any conventional nutrient brothcontaining assimilable carbon and nitrogen source. A comparativestatement given in Table 1 explains the novelty of our invention incomparison with prior art known in this field. TABLE 1 Comparativestatement Type of Reference paper or Source of (Prior art) ink deinkingagent Remarks Patent Impact Chemical & a surfactant, Not US6022423 inkand abrading the practical on office paper and washing a large waste thedeinked paper scale using a special device to put whole sheet US5525193Toner, Monocomponent cellulase Enzyme impact purified from technology isink cellulolytic enzymes expensive from of various mixed microorganismsoffice or genetically waste engineered orgainsm which produces onlymonocomponent cellulase Gubitz et al. Xerox and Endogluconases andEnzyme 1998 laser- hemicellulases technology is printed from fungiexpensive. paper GB2304741 Laser- Enzyme containing Purification printedor a resistant and xerographic binder application paper of enzymetechnology is still expensive Patent Office Cellulase Expensive EP717144 waste enzyme paper technology JP06346390 Office Contacting withEnzyme high waste cellulase at temperature paper 40° C. 1 h and pressureunder pressure will make the cost of technology not very practical.JP2160984 Office Contacting Adjustment of waste pulp with pH and enzymepaper lipase technology enzyme under will not neutral or make it veryalkaline practical. conditions KR9303705 Office Contacting The inkfloats waste pulp with the on the surface paper culture of the and thepulp yeast Hansenula has to be polymorpha extensively which degradeswashed the ink- based resin. JP10313859 For Thermostable Recommen-deddecolor- alkaline for surfactant ization on cellulase composition, as ofIndian from a a fiber treat- ink bacterium ment agent and as an Indianink decolor- ization agent. Our For Xerox Direct contact No enzyme, noinvention and inkjet- of pulp temp-erature or printed slurry with pHadjustment, paper pulp the bacterium the pulp and NIO/DI/32 the waterare for 72 h to clear and get complete washing is decolorization onlyoptional. of the pulp and clear water

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[0041] In the drawings accompanying the specification,

[0042]FIG. 1 shows the radiance of Xerox paper pulp (XP) is lowest incomparison with that of recycled paper pulp (RP) and biologicallydeinked pulp (BP);

[0043]FIG. 2 shows the ratio of radiance of biologically deinked paperto that of recycled paper;

[0044]FIG. 3 compares the deinking done by the present invention onpapers of three different photocopier machines;

[0045]FIG. 4 compares the radiance of decolorized paper pulp after 4days at different concentration of inoculum;

[0046]FIG. 5 compares the reflectance ratio of the deinked paper pulp byat different concentrations of inoculum;

[0047]FIG. 6 compares the radiance ratio of the deinked paper pulp withthe number of days;

[0048]FIG. 7 shows the ratio of radiance between recycled paper anddeinked paper;

[0049]FIG. 8 shows that with an inoculam concentration of 2 ml, maximumbrightness is achieved after 72 hours and

[0050]FIG. 9 shows that with an inoculum concentration of 10 ml, maximumbrightness is achieved by 72 hours.

[0051] The present invention is further described with reference to theaccompanying examples, which are given by way of illustration andtherefore, should not be construed to limit the scope of the presentinvention in any manner.

EXAMPLE 1

[0052] The bacterial isolate NIO/DI/32 was isolated from the coastalesturine sediment, Dona Paula, Goa, India in nutrient agar mediumcontaining beef extract and peptic digest of animal tissue and agar insea water with its salinity diluted to 50%. The culture was maintainedin the slants of nutrient agar medium for all further experiments.

[0053] The said bacterium can be grown in nutrient broth containing beefextract, peptic digest of animal tissue in sea water with its salinitydiluted to 50%. The bacterium is grown at room temperature (30° C.) forabout 4 days, the bacterial cells are collected by centrifugation understerile conditions, diluted appropriately to get optical density of 1 at660 nm using a spectrophotometer. Xerographic paper printed with impactink from HP machine are pulped by soaking in hot water for a minimum of2 hrs, macerated in a conventional domestic mixer with surfactant suchas Tween 80. An example for the process for deinking involves suspendingsuch a pulp at least at 6% consistency (6 g wet pulp in 100 ml of water)in sea water with its salinity diluted to 50%, inoculating with 20%bacterial suspension prepared as described above and incubating at roomtemperature for a minimum of 4 days to get completely bleached pulp withthe ink totally disappearing from the supernatant water. The pulp can bediluted, aerated from bottom to remove free contaminating particles,salts and bacterial cells. A surfactant such as Tween 80 can be added at1% concentration for flotation of any residual ink particles. The pulpis filtered over a Buchner funnel under suction, pressed with flatstainless steel plates to make the pulp sheet uniform in thickness. Theradiance of the resultant sheet is read from 412 to 684 nm and theradiance expressed in Lux units (Lu). One LU is equivalent toμW/cm²/nm/Sr. The ratio of radiance between recycled paper available inany stationery shop and biologically deinked paper is taken as a measureof brightness.

[0054] Accordingly, FIG. 1 shows the radiance of Xerox paper pulp (XP)is lowest in comparison with that of recycled paper pulp (RP) andbiologically deinked pulp (BP). This brightness was achieved 4 daysafter inoculation with the said bacterium. As the target was to achievebrightness of recycled paper, the Applicants have shown the same data asratio of radiance of Xerox paper to recycled paper and similarly, theratio of radiance of biologically deinked paper to that of recycledpaper is shown in FIG. 2.

[0055] Xerographic printed paper obtained from various Xerox machineswere compared for their efficiency in being deinked by the saidbacterium. Accordingly FIG. 3 shows that out of 3 different machines,Xerox paper obtained from Lanier machine were deinked effectively by theprocess described in the present invention.

EXAMPLE 2

[0056] As seen in the previous example, the bacterium could grow in theplain paper pulp suspended in water, and bleach the pulp in 4 days, theXerox toner (HP make) at 1% concentration was suspended in sterile seawater and inoculated with the said bacterial suspension and incubated atroom temperature for 15 days. The control flask did not receive anybacterial inoculum. The contents of experimental flask and the controlflask were filtered over pre-weighed filter paper, rinsed with steriledistilled water to remove salts and dried to a constant weight at 60° C.The difference in weight of residual toner powder was compared in thetwo sets.

[0057] Accordingly, in the experimental flask after 15 days the dryweight was 143 mg whereas, in the control flask it was 220 mg. Thus,almost 65% toner was degraded in the inoculated flasks. Besides, thewater in the experimental flask became almost colorless.

EXAMPLE 3

[0058] The ability of the bacterial isolate having accession numberNIO/DI/32 (also being deposited at an international depository) to deinkink-jet printed paper was tried as follows:

[0059] The inkjet printed-paper was prepared into pulp as described inExample 1 and inoculated with the said bacterium as described inExample 1. However, the inoculum dose varied from 2 ml to 10 ml with theincrement of 2 ml. The other procedures used were the same as describedn the Example 1.

[0060] Accordingly, FIG. 4 shows radiance of decolorized paper pulpafter 4 days in comparison with Xerox and recycled paper. The radianceof biologically deinked paper was more than the recycled paper and therewas not much difference between inoculum concentration of 6 to 10 ml inthe final radiance achieved.

[0061]FIG. 5 shows the ratio of reflectance between Xerox paper torecycled paper in comparison with paper pulp deinked using differentconcentrations of the said bacterial suspension. The brightness achievedby using 8 ml or 10 ml inoculum was almost similar.

EXAMPLE 4

[0062] The deinking of inkjet-printed paper in relation to time ofincubation (in days) was carried out as follows:

[0063] The preparation of pulp, inoculum and experimental set up weresame as in the previous example, but the inoculum concentration usedhere was 10 ml and radiance of the pulp was tested on day 2, 4, 6 and 8days after incubating the pulp with the said bacterial culture.

[0064] Accordingly, FIG. 6 shows that by day 6 maximum brightness isachieved and here also the radiance of biologically deinked pulp wasslightly greater than that of recycled paper purchased from the market.The control was the inkjet printed paper pulp.

[0065]FIG. 7 shows the ratio of radiance between recycled paper anddeinked paper. The control was the ink-jet printed paper pulp whichshowed lowest radiance ratio.

EXAMPLE 5

[0066] Ability of the said bacterium to deink the inkjet—printed paperwith two concentrations of the inoculum at varying incubation period wascompared to arrive at a combination where deinking is achieved in ashortest time.

[0067] Accordingly FIG. 8 shows that with an inoculam concentration of 2ml, maximum brightness is achieved after 72 hours.

[0068]FIG. 9 also shows that with an inoculum concentration of 10 ml,maximum brightness is achieved by 72 hours.

1. A process for biological deinking of office waste paper inclusive ofxerographic and inkjet-printed paper printed with non-impact andnon-dispersible ink, said process comprises: (a) growing coccoidbacterial isolate deposited at National Institute of Oceanography, DonaPaula, Goa 403 043, India having accession No. NIO/DI/32 and beingdeposited at an international depository ______ having accession number______, in a nutrient broth containing beef extract, peptic digest ofanimal tissue and salinity ranging between 30 to 35 parts per thousandfor at least 4 days; (b) adding the resulting biomass of step (a) at 20%concentration to inoculate paper pulp diluted to at least 6% consistencysuspended in sea water with salinity diluted to 50%; (c) incubating theinoculated pulp for a minimum period of 96 hours followed by dilutingthe pulp tenfold; (d) adding 1% by wt. of a surfactant and aerating forat least 10 minutes with compressed air to let the stray residual inkparticles and contaminants flow out of the container, and (e) filteringthe pulp of step (d) over a funnel under suction, to get a sheet of pulpwith uniform thickness and reading the brightness by radiancemeasurement.
 2. A process as claimed in claim 1, wherein in step (a),the bacterium is grown for a minimum of 4 days in nutrient brothcontaining beef extract and peptic digest of animal tissue in sea waterwith salinity diluted to 50%.
 3. A process as claimed in claim 1,wherein in step (b), the resulting bacterial biomass is concentrated bycentrifugation and diluted to get final optical density of 1.0 measuredat 660 nm in a spectrophotometer.
 4. A process as claimed in claim 1,wherein the diluted bacterial culture is inoculated to at least 6% pulpsuspended in seawater with salinity diluted to 50% and incubated for aminimum period of 4 days within to completely beach the pulp.
 5. Aprocess as claimed in claim 1, wherein the resulting bleached pulp isdiluted tenfold, to which 1% surfactant is added, aerated usingcompressed air, and any free residual ink particles and contaminants areallowed to flow out of the solution.
 6. A process as claimed in claim 1,wherein after step (d) the xerographic or inkjet-printed paper is soakedin hot water for 1-2 hours and macerated after adding 1% surfactant topulp.
 7. A process as claimed in claim 6, wherein the paper is maceratedusing conventional mixers.
 8. A process as claimed in claim 1, whereinin step (e), the washed pulp is filtered over a Buchner funnel undersuction to get a pulp sheet of uniform thickness.
 9. A process asclaimed in claim 1, wherein the pulp sheet is pressed at 60° C. for aminimum of 4-5 hours to make it uniform and dried.
 10. A process asclaimed in claim 1, wherein the radiance of the resultant sheet is readfrom 412 to 684 nm and the radiance expressed as Lux units (LU) {whereinone LU is equivalent to μW/cm²/nm/Sr}.
 11. A process as claimed in claim1, wherein the pulp sheet made out of recycled paper is used as areference.
 12. A process as claimed in claim 1, wherein in steps (a) and(b), pure water containing 1.5% by wt of sodium chloride can be used inthe place of sea water.